JPH02154987A - Finned heat exchanger - Google Patents

Abstract

PURPOSE:To permit the restriction of the ventilating resistance of airflow as well as the improvement of heat exchanging capacity by a method wherein the title heat exchanger is constituted of flat plate fins, provided with a plurality of stages of flat grooves, notched at both ends of the rims, and hollow flat tubes, inserted into the flat grooves from the side surface thereof and enclosed by long sides and short sides, while the thickness of the flat tube in the direction of the short sides thereof and a pitch in the direction of the steps are specified. CONSTITUTION:Flat tubes 10, inserted into and adhered to the flat grooves 8 of flat plate fins 7 from the side surfaces thereof, are constituted of long sides 10a, short sides 10b and partitioning plates 10c, dividing the inside of the pipes, while a plurality of the flat tubes are arranged with a pitch Pd so that the long sides 10a of the flat tubes 10 are arranged in parallel to the direction of airflow A. The thickness (t) in the direction of the short sides 10b of the flat tube 10 is specified within 1-3mm while the pitch Pd is specified within 8-12mm. According to this method, the density of the flat tube 10 and the flat plate fin 7 may be increased and the remarkable increase of heat exchanging capacity as well as the peak point thereof may be obtained while the increase of the ventilating resistance of airflow, which is generated by the increase of the density of the flat tube 10 and the flat plate fin 7, may be restrained by the employment of thin type flat tubes 10.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to a finned heat exchanger that can be used in air conditioning equipment, refrigeration equipment, automobile equipment, etc., and that transfers heat between fluids such as refrigerant and air. .

BACKGROUND OF THE INVENTION In recent years, finned heat exchangers have been required to be more compact in terms of equipment design, and efforts have been made to improve efficiency by improving the fin shape and tube inner surface shape.

Hereinafter, the conventional finned heat exchanger mentioned above will be explained with reference to the drawings.

8 and 9 show the shape of a conventional finned heat exchanger, FIG. 10 shows a fin shape constituting a conventional finned heat exchanger, and FIG. 11 shows a circular tube shape.

In FIGS. 8 to 11, reference numeral 1 indicates a plurality of flat plate fins arranged in parallel at regular intervals, with a constant pitch P6 in the step direction.
Oval holes 2 arranged in
is provided. Reference numeral 4 denotes a circular tube that is inserted into the circular hole 2 of the flat fin and is tightly fitted.The circular tubes 4 are connected to each other by bends 5 at both ends to form a refrigerant R flow path in the tube, and a plurality of spirals 16 are provided in the tube. ing. In addition, conventionally, the outer diameter Do of the circular tube 4 was set to 7 to 10 mm from the viewpoint of performance and workability.
A range of 21 to 25 mm was mainly used for the pitch Pd in the step direction.

The operation of the finned heat exchanger constructed as described above will be described below with reference to FIGS. 12 and 13.

Heat exchange is performed between the airflow flowing between the flat plate fins 1 and the refrigerant R flowing in the circular tube 4 via the flat plate fins 1 and the circular tube 4t. At that time, the looper 3 is placed on the surface of the flat fin 1.
Since they are provided separately, the development of a temperature boundary layer in the airflow generated on the surface of the flat fin 1 is suppressed, and the heat transfer coefficient between the air mA and the flat fin 1 is improved. In addition, since the spiral groove 6 promotes turbulence of the refrigerant R within the circular tube 4, the heat transfer coefficient between the circular tube 4 and the refrigerant R is improved.

Problems to be Solved by the Invention However, in the above configuration, the outer diameter Do of the circular tube 4
is large, so the ventilation resistance of the air NaA crossing the circular tube 4 is large, and the ventilation resistance of the airflow A is reduced by increasing the stepwise pitch Pd of the circular tube 4, and the fin efficiency is reduced by decreasing the stepwise pitch Pd. Since the improvement of the actual passing wind speed and the improvement of the actual passing wind speed have contradictory effects, there has been a problem in that it is impossible to expect a performance improvement over the conventional one when ventilation resistance is taken into consideration.

In view of the above-mentioned problems, the present invention provides a finned heat exchanger that significantly improves heat exchange capability while suppressing airflow resistance to the same level as before.

Means for Solving the Problems In order to solve the above problems, the heat exchanger with fins of the present invention has a flat plate fin having a plurality of flat grooves formed by cutting out both ends of the front and rear edges, and flat grooves arranged parallel to each other at regular intervals. It consists of a hollow flat tube that is inserted into the flat grooves of the flat plate fins lined up from the measuring surface and surrounded by long sides and short sides, and the flat tubes are arranged in multiple stages with their long sides parallel to each other. The thickness of the flat tube in the short side direction is in the range of 1 to 3 mm, and the pitch Pd in the step direction of the flat tube is limited in the range of 8 to 12 mrn.

Effect of the present invention With the above-described configuration, the density of the flat tube and the flat plate fin can be increased, and the heat exchange capacity can be greatly improved by increasing the heat transfer area, improving the heat transfer coefficient, and improving the fin efficiency. The increase in airflow resistance caused by the increased density of the tube and flat fins can be suppressed by using thin flat tubes.

EXAMPLE Hereinafter, a finned heat exchanger according to an example of the present invention will be described with reference to the drawings.

1 and 2 show the shape of a finned heat exchanger in an embodiment of the present invention, and FIG. 3 shows the shape of a flat fin,
FIG. 4 shows the shape of the flat tube. In FIGS. 1 to 4, reference numeral 7 denotes a plurality of flat plate fins arranged in parallel at regular intervals, and flat grooves formed by cutting out both front and rear edges in the air inflow direction and arranged at a constant pitch Pd in the stepped direction. 8 and a looper 9 divided in the air inflow direction are provided on the surface of the flat plate fin 7. Reference numeral 10 denotes a flat tube that is inserted into the flat groove 8 of the flat plate fin from the measuring surface and is in close contact, and is composed of a long side 10a, a short side 10b, and a dividing plate 10c that divides the inside of the tube.
a is the air inflow direction. A plurality of parallel stages are provided with a stage pitch Pd. 11 is a header connected to both ends of the flat tube 10, and together with the flat tube 10 constitutes an internal flow path for the refrigerant R.

Further, drain channels 12 are provided in the flat plate fin 7 before and after the flat groove 8. Furthermore, the thickness t of the flat tube 10 in the direction of the short side 10b
is defined in the range of 1 to 3 mm, and the step pitch Pd is defined in the range of 8 to 12 mm.

The operation of the finned heat exchanger constructed as above will be described below with reference to FIGS. 5 and 6.

Heat exchange is performed between the airflow A flowing between the flat fins 7 and the refrigerant R flowing through the flat tube 10 via the ladder 11 via the flat fins 7 and the flat tube 10.

At this time, since the looper 9 is provided on the surface of the flat fin 7, the development of a temperature boundary layer of the airflow A generated on the surface of the flat fin 7 is suppressed, and the heat transfer coefficient between the airflow A and the flat fin 7 is reduced. Improvements are being made.

Moreover, the inside of the flat tube 10 is made into microchannels by the dividing plate 10c, and the heat transfer coefficient between the flat tube 10 and the refrigerant R is improved.

In addition, by adopting the thin flat tube 10, the ventilation resistance of the airflow A can be lowered, and with the same ventilation resistance standard as the conventional example, it is possible to increase the density of the flat tube 10 and the flat plate fins 7, increasing the heat transfer area and increasing the heat transfer area. Heat exchange capacity can be significantly improved by improving the transfer coefficient and fin efficiency.

Further, FIG. 7 shows the results of an analysis of the relationship between the stage pitch Pd of the flat tubes 10 of the finned heat exchanger according to the embodiment of the present invention, the temperature efficiency, and the ventilation resistance. According to this result, the thickness t in the short axis 10b direction of the flat tube 10 is 1 to 3
When the step pitch Pd is 8 to 12 mm in mm, the maximum range of temperature efficiency can be obtained without increasing the ventilation resistance of the air flow A.

Furthermore, even when this heat exchanger is used as an evaporator and condensed water accumulates on the outer surface of the heat exchanger, since the drainage channel 12 is ensured on the surface of the flat plate fins 7, the condensed water will flow through the flat tubes 10. It does not accumulate on the upper surface and falls to the lower level along the drainage channel 12, so that ventilation resistance does not increase.

As described above, according to this embodiment, the flat plate fin 7 has a plurality of flat grooves 8 formed by cutting out both ends of the front and rear edges, and the flat grooves of the flat plate fin 7 are arranged in parallel at regular intervals. It consists of a hollow flat tube 10 that is inserted from the measuring surface into the tube 8 and surrounded by a long side 10a and a short side 10b, and the flat tube 10
is composed of multiple stages with the long sides 10a parallel to each other, the thickness t of the flat tube 10 in the short side 10b direction is in the range of 1 to 3 mm, and the pitch Pd of the flat tube 10 in the step direction is 8 to 12 mm.
By limiting the range to the above range, it is possible to increase the density of the flat tube 10 and the flat plate fin 7, and by increasing the heat transfer area, improving the heat transfer coefficient, and improving the fin efficiency, the heat exchange capacity is significantly improved and its peak point is increased. In addition, by adopting the thin flat tube 10, the increase in ventilation resistance of the airflow A caused by the high density of the flat tube 10 and the flat plate fins 7 can be suppressed, and the ventilation resistance level can be suppressed to the same level as the conventional example. be able to. In addition, when this effect is applied to downsizing the finned heat exchanger, it is possible to reduce the size of the conventional finned heat exchanger (outside the circular tube 'tV 7
The volume can be reduced to about half compared to the 21 mm step pitch. Further, since the flat tube 10 is inserted into the flat groove 8 from the measured surface of the flat plate fin 7, it is extremely easy to insert the flat tube 10 into tight contact. Furthermore, even when this heat exchanger is used as an evaporator, condensed water can be drained well and ventilation resistance does not increase.

Effects of the Invention As described above, the present invention provides a flat plate fin having a plurality of flat grooves formed by cutting out both ends of the front and rear edges, and a flat groove in the flat grooves arranged in parallel at regular intervals. It consists of a hollow flat tube inserted into the tube and surrounded by a long side and a short side, and the flat tube has a plurality of stages with the long sides parallel to each other, and the thickness t of the flat tube in the short side direction is 1. ~3 rom, and the pitch Pd of the flat tubes in the row direction is 8 to 12 mm.
By limiting the range to , it is possible to increase the density of the flat tube and flat plate fin, and by increasing the heat transfer area, improving the heat transfer coefficient, and improving the fin efficiency, it is possible to significantly improve the heat exchange capacity and obtain its peak point. In addition, the increase in airflow resistance caused by the high density of the flat tube and flat plate fins can be suppressed by using thin flat tubes, and the ventilation resistance can be suppressed to the same level as the conventional example. Furthermore, when this effect is applied to downsizing a finned heat exchanger, the volume can be reduced to about half that of a conventional finned heat exchanger.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the shape of a finned heat exchanger in an embodiment of the present invention, Fig. 2 is a perspective view of the main part of Fig. 1, and Fig. 3 is a plan view showing the shape of the flat plate fin in Fig. 1. Figure 4 is a cross-sectional view showing the shape of the flat tube in Figure 1, Figure 5 is a cross-sectional view showing the flow state of airflow in the operating condition of Figure 1, and Figure 6 is a cross-sectional view showing the refrigerant circuit in Figure 1. 7 is a graph showing the relationship between the step pitch of the flat tube shown in FIG. 1, temperature efficiency, and ventilation resistance. FIG. 8 is a perspective view showing the shape of a conventional finned heat exchanger. The figure is a perspective view of the main part of FIG. 8, FIG. 10 is a plan view showing the shape of the flat fin in FIG. 8, FIG. 11 is a sectional view showing the shape of the circular tube in FIG. 8, and FIG. The state of air flow in the operating condition shown in Figure 8! ! FIG. 13 is a cross-sectional view showing the flow state of the refrigerant in the operating state of FIG. 8. 7... Flat plate fin, 8... Flat groove, 10... Flat tube. Name of agent: Patent attorney Shigetaka Awano and 1 other person (Fig. 1) /, National Permit Article 12--- Kakuganfi I4 Anare Rubako IF7 Road to Torihiramiya Runo 10--1 Even 乎 鵞n Fig. 10 fig.

Claims (1)

[Claims] A flat plate fin has a plurality of flat grooves formed by cutting out both ends of the front and rear edges, and is inserted from the measuring surface into the flat grooves of the flat plate fins arranged in parallel at regular intervals, and is surrounded by long and short sides. The flat tube consists of a plurality of stages with their long sides parallel to each other, and the thickness t of the flat tube in the short side direction is in the range of 1 to 3 mm, and the stages of the flat tube are A finned heat exchanger characterized in that the directional pitch Pd is in the range of 8 to 12 mm.